1897 Mindanao earthquakes

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1897 Mindanao earthquakes
1897 Mindanao earthquakes is located in Mindanao
1897 Mindanao earthquakes
1897 Mindanao earthquakes is located in Philippines
1897 Mindanao earthquakes
Local date September 20, 1897 (1897-09-20), September 21, 1897 (1897-09-21)
Magnitude 7.4, 7.5 Ms
Epicenter 6°00′N 122°00′E / 6.0°N 122.0°E / 6.0; 122.0Coordinates: 6°00′N 122°00′E / 6.0°N 122.0°E / 6.0; 122.0
Max. intensity VII, IX Mercalli intensity scale
Tsunami Both
Casualties None reported, 13 to 100+

The 1897 Mindanao earthquakes occurred on 20 September at 19:06 UTC and 21 September at 05:12 UTC. The estimated epicentres of the two earthquakes are identical, lying just off the southwestern coast of Mindanao in the Philippines, south of Basilan island. The earthquakes were originally given estimated magnitudes of 8.6 and 8.7 on the surface wave magnitude scale by Charles Richter,[1][2] but these were revised downwards by Katsuyuki Abe to 7.4 and 7.5 Ms, respectively.[3] Contemporary reports noted that with few exceptions, all the masonry buildings in Zamboanga and Basilan were left in ruins.[4]

Both earthquakes triggered tsunamis, with the second being quite destructive, with a maximum run-up of 7.0 m.[5] The tsunami was noted all along the southwest coast of Negros, the west coast of Panay, the south coast of Palawan, the west coast of Mindanao, and the east coast of Borneo.[6] At least 13 died as a result of the second tsunami, with a hundred or more casualties also being reported.[2]

See also[edit]

References[edit]

  1. ^ "Comments for the 20/9 Earthquake". Significant Earthquake Database. National Geophysical Data Center. Retrieved 27 June 2015. 
  2. ^ a b "Comments for the 21/9 Earthquake". Significant Earthquake Database. National Geophysical Data Center. Retrieved 27 June 2015. 
  3. ^ Ye L., Lay T. & Kanamori H. (2012). "Intraplate and interplate faulting interactions during the August 31, 2012, Philippine Trench earthquake (M w 7.6) sequence". Geophysical Research Letters. L24310 (24): n/a. Bibcode:2012GeoRL..3924310Y. doi:10.1029/2012GL054164. 
  4. ^ Coronas, José (1899). La actividad séismica en el Archipiélago filipino durante el año 1897 (in Spanish). Manila Observatory: Tipolitografía del Observatorio. 
  5. ^ "Comments for the 21/9 Tsunami Event". NGDC/WDS Tsunami Event Database. National Geophysical Data Center. Retrieved 27 June 2015. 
  6. ^ Saderra Masó, Miguel (1904). Volcanoes and seismic centers of the Philippine Archipelago. Census of the Philippine Islands. Bulletin 3. Bureau of the Census. pp. 42–44.